This invention relates to a boat trailer, and more particularly to a bolster bracket for a boat trailer.
A typical boat trailer includes an open frame or chassis made from structural steel channel members, including steel channel cross or transverse frame members. Elongated, padded bolsters are mounted upon, and above, the transverse channel frame members by an elongated vertical support bracket, the top end of which is preferably pivoted or swivelly connected to the bottom of each bolster. Each support bracket is provided with an elongated vertical central slot receiving a U-bolt extending around, or encompassing, a cross-sectional portion of the transverse frame member and secured in place by a pair of nuts.
However, because of the weight of the boat upon the bolsters, and the constant vibration of the boat trailer in transit, the frictional engagement between the nuts of the U-bolt and the support bracket is oftentimes insufficient to prevent the brackets from slipping upon the surface of the transverse frame member. Accordingly, one or more of the bolsters, or one end portion of a bolster, is lowered relative to the other bolsters or bolster portions, automatically lowering that portion of the supported boat, so that the boat is carried in an unbalanced or tilted attitude.
Attempts have been made to minimize or eliminate the accidental slipping of the support bracket upon the transverse frame member, by inserting high frictional washers, or washers having claws projecting therefrom, between the nuts and the corresponding threaded legs of the U-bolt, so that the highly frictional washer surfaces will more firmly grip, or bite into the surface of the upright support member or bracket. However, even high frictional washer surfaces and washer claws eventually wear to lessen their gripping and holding effectiveness.